本文介绍了如何在Android项目中集成并定制zXing二维码扫描库，包括解决运行时崩溃问题、修改屏幕方向、精简界面及自定义扫描效果等关键步骤。
第一次使用 zXing，觉得真心无力！废话不多说。
拿到 zXing 源码，好多文件。原谅我的无知，最后发现只有 android 文件夹是需要的。android-core 里面的CameraConfigurationUtils.java请复制到android的的项目里面，因为需要。然后 zXing 的 github 有可以直接下载 core.jar 的地址，下载一个添加进去。因为 zXing 是依赖它的。
然后运行项目，是一个条形扫描器。很专业的。但是我们的项目可能不太需要。这个步骤，可能运行后崩溃。这个是因为 core 添加的过程中出现了问题。在 build path 里面配置排序，将 core 的 jar 包排到第一位即可。
之后就是精简，初次接触安卓项目。好多东西不敢动，所以，只是去除了不需要的一些菜单。这个仔细研究下，估计就会了。主要是扫描界面的样式。
zXing 默认是横屏，必须更改为竖屏。
目前我是用的3.2.1版本的 zXing。
第一步：修改AndroidManifest工程清单，AndroidManifest中CaptureActivity的screenOrientation属性改为portrait
第二步：删除CaptureActivity中把onResume方法中的无用代码：
// if (prefs.getBoolean(PreferencesActivity.KEY_DISABLE_AUTO_ORIENTATION, true)) {
// setRequestedOrientation(getCurrentOrientation());
// } else {
// setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE);
// }if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
} else {
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}// rect.left = rect.left * cameraResolution.x / screenResolution.x;
// rect.right = rect.right * cameraResolution.x / screenResolution.x;
// rect.top = rect.top * cameraResolution.y / screenResolution.y;
// rect.bottom = rect.bottom * cameraResolution.y / screenResolution.y;
rect.left = rect.left * cameraResolution.y / screenResolution.x;
rect.right = rect.right * cameraResolution.y / screenResolution.x;
rect.top = rect.top * cameraResolution.x / screenResolution.y;
rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;第五步：修改DecodeHandler中的decode(byte[] data, int width, int height)方法：
PlanarYUVLuminanceSource source = activity.getCameraManager().buildLuminanceSource(data, width, height);
byte[] rotatedData = new byte[data.length];
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++)
rotatedData[x * height + height - y - 1] = data[x + y * width];
}
int tmp = width;
width = height;
height = tmp;
data = rotatedData;如果只是做了第一步，就会导致扫描后得到的图片是横着的，而且，取景框也和屏幕上显示的范围不一直。所以下面的都必须做。否则会出现异常。
然后，就是修改扫描页面了。我不懂的是，google 的扫描的界面仅仅是闪烁红线+一个黄色的点，看起来非常不爽。
没关系，该改改：
viewfinderView是扫面时候的界面。我这里修改为了四个角+一条上下移动的扫描线。直接上代码
public final class ViewfinderView extends View {
private static final int[] SCANNER_ALPHA = {0, 64, 128, 192, 255, 192, 128, 64};
private static final long ANIMATION_DELAY = 10L;//刷新界面的时间
private static final int CURRENT_POINT_OPACITY = 0xA0;
private static final int MAX_RESULT_POINTS = 20;
private static final int POINT_SIZE = 6;
/******************************/
private static final String TAG = "log";
/**
* 刷新界面的时间
*/
private static final int OPAQUE = 0xFF;
/**
* 四个绿色边角对应的长度
*/
private int ScreenRate;
/**
* 四个绿色边角对应的宽度
*/
private static final int CORNER_WIDTH = 6;
/**
* 扫描框中的中间线的宽度
*/
private static final int MIDDLE_LINE_WIDTH = 6;
/**
* 扫描框中的中间线的与扫描框左右的间隙
*/
private static final int MIDDLE_LINE_PADDING = 5;
/**
* 中间那条线每次刷新移动的距离
*/
private static final int SPEEN_DISTANCE = 5;
/**
* 手机的屏幕密度
*/
private static float density;
/**
* 字体大小
*/
private static final int TEXT_SIZE = 16;
/**
* 字体距离扫描框下面的距离
*/
private static final int TEXT_PADDING_TOP = 30;
/**
* 中间滑动线的最顶端位置
*/
private int slideTop;
/**
* 中间滑动线的最底端位置
*/
private int slideBottom;
boolean isFirst;
/****************************/
private CameraManager cameraManager;
private final Paint paint;//画笔对象的引用
private Bitmap resultBitmap;
private final int maskColor;
private final int resultColor;
private final int laserColor;
private final int resultPointColor;
private int scannerAlpha;
private List<ResultPoint> possibleResultPoints;
private List<ResultPoint> lastPossibleResultPoints;
// This constructor is used when the class is built from an XML resource.
public ViewfinderView(Context context, AttributeSet attrs) {
super(context, attrs);
density = context.getResources().getDisplayMetrics().density;
//将像素转换成dp
ScreenRate = (int)(20 * density);//四个角的长度
// Initialize these once for performance rather than calling them every time in onDraw().
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
Resources resources = getResources();
maskColor = resources.getColor(R.color.viewfinder_mask);
resultColor = resources.getColor(R.color.result_view);
laserColor = resources.getColor(R.color.viewfinder_laser);
resultPointColor = resources.getColor(R.color.possible_result_points);
scannerAlpha = 0;
possibleResultPoints = new ArrayList<>(5);
lastPossibleResultPoints = null;
}
public void setCameraManager(CameraManager cameraManager) {
this.cameraManager = cameraManager;
}
@SuppressLint("DrawAllocation")
@Override
public void onDraw(Canvas canvas) {
if (cameraManager == null) {
return; // not ready yet, early draw before done configuring
}
Rect frame = cameraManager.getFramingRect();//中间的扫描框，你要修改扫描框的大小，去CameraManager里面修改
Rect previewFrame = cameraManager.getFramingRectInPreview();
if (frame == null || previewFrame == null) {
return;
}
//初始化中间线滑动的最上边和最下边
if(!isFirst){
isFirst = true;
slideTop = frame.top;
slideBottom = frame.bottom;
}
//获取屏幕的宽高
int width = canvas.getWidth();
int height = canvas.getHeight();
// Draw the exterior (i.e. outside the framing rect) darkened
paint.setColor(resultBitmap != null ? resultColor : maskColor);
//画出扫描框外面的阴影部分，共四个部分，扫描框的上面到屏幕上面，扫描框的下面到屏幕下面
//扫描框的左边面到屏幕左边，扫描框的右边到屏幕右边
canvas.drawRect(0, 0, width, frame.top, paint);
canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint);
canvas.drawRect(0, frame.bottom + 1, width, height, paint);
if (resultBitmap != null) {
// Draw the opaque result bitmap over the scanning rectangle
paint.setAlpha(CURRENT_POINT_OPACITY);
canvas.drawBitmap(resultBitmap, null, frame, paint);
} else {
// Draw a red "laser scanner" line through the middle to show decoding is active
paint.setColor(laserColor);
/*
* 去掉系统自带的那条红线
paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
int middle = frame.height() / 2 + frame.top;
canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1, middle + 2, paint);
*/
//*******画扫描框边上的角，总共8个部分********//
canvas.drawRect(frame.left, frame.top, frame.left + ScreenRate,
frame.top + CORNER_WIDTH, paint);
canvas.drawRect(frame.left, frame.top, frame.left + CORNER_WIDTH, frame.top
+ ScreenRate, paint);
canvas.drawRect(frame.right - ScreenRate, frame.top, frame.right,
frame.top + CORNER_WIDTH, paint);
canvas.drawRect(frame.right - CORNER_WIDTH, frame.top, frame.right, frame.top
+ ScreenRate, paint);
canvas.drawRect(frame.left, frame.bottom - CORNER_WIDTH, frame.left
+ ScreenRate, frame.bottom, paint);
canvas.drawRect(frame.left, frame.bottom - ScreenRate,
frame.left + CORNER_WIDTH, frame.bottom, paint);
canvas.drawRect(frame.right - ScreenRate, frame.bottom - CORNER_WIDTH,
frame.right, frame.bottom, paint);
canvas.drawRect(frame.right - CORNER_WIDTH, frame.bottom - ScreenRate,
frame.right, frame.bottom, paint);
//绘制中间的线,每次刷新界面，中间的线往下移动SPEEN_DISTANCE
slideTop += SPEEN_DISTANCE;
if(slideTop >= frame.bottom){
slideTop = frame.top;
}
canvas.drawRect(frame.left + MIDDLE_LINE_PADDING, slideTop - MIDDLE_LINE_WIDTH/2, frame.right - MIDDLE_LINE_PADDING,slideTop + MIDDLE_LINE_WIDTH/2, paint);
//画扫描框下面的字
paint.setColor(Color.WHITE);
paint.setTextSize(TEXT_SIZE * density);
paint.setAlpha(0x40);
paint.setTypeface(Typeface.create("System", Typeface.BOLD));
canvas.drawText(getResources().getString(R.string.msg_default_status), frame.left, (float) (frame.bottom + (float)TEXT_PADDING_TOP *density), paint);
//****************************************//
float scaleX = frame.width() / (float) previewFrame.width();
float scaleY = frame.height() / (float) previewFrame.height();
/*
* 去掉那个小圆点，大概是这个
List<ResultPoint> currentPossible = possibleResultPoints;
List<ResultPoint> currentLast = lastPossibleResultPoints;
int frameLeft = frame.left;
int frameTop = frame.top;
if (currentPossible.isEmpty()) {
lastPossibleResultPoints = null;
} else {
possibleResultPoints = new ArrayList<>(5);
lastPossibleResultPoints = currentPossible;
paint.setAlpha(CURRENT_POINT_OPACITY);
paint.setColor(resultPointColor);
synchronized (currentPossible) {
for (ResultPoint point : currentPossible) {
canvas.drawCircle(frameLeft + (int) (point.getX() * scaleX),
frameTop + (int) (point.getY() * scaleY),
POINT_SIZE, paint);
}
}
}
if (currentLast != null) {
paint.setAlpha(CURRENT_POINT_OPACITY / 2);
paint.setColor(resultPointColor);
synchronized (currentLast) {
float radius = POINT_SIZE / 2.0f;
for (ResultPoint point : currentLast) {
canvas.drawCircle(frameLeft + (int) (point.getX() * scaleX),
frameTop + (int) (point.getY() * scaleY),
radius, paint);
}
}
}
*/
// Request another update at the animation interval, but only repaint the laser line,
// not the entire viewfinder mask.
postInvalidateDelayed(ANIMATION_DELAY,
frame.left - POINT_SIZE,
frame.top - POINT_SIZE,
frame.right + POINT_SIZE,
frame.bottom + POINT_SIZE);
}
}
public void drawViewfinder() {
Bitmap resultBitmap = this.resultBitmap;
this.resultBitmap = null;
if (resultBitmap != null) {
resultBitmap.recycle();
}
invalidate();
}
/**
* Draw a bitmap with the result points highlighted instead of the live scanning display.
*
* @param barcode An image of the decoded barcode.
*/
public void drawResultBitmap(Bitmap barcode) {
resultBitmap = barcode;
invalidate();
}
public void addPossibleResultPoint(ResultPoint point) {
List<ResultPoint> points = possibleResultPoints;
synchronized (points) {
points.add(point);
int size = points.size();
if (size > MAX_RESULT_POINTS) {
// trim it
points.subList(0, size - MAX_RESULT_POINTS / 2).clear();
}
}
}
}
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